The present invention relates to a method of piercing a sealed capsule on a coffee machine.
More specifically, the present invention relates to a method of piercing a sealed capsule on a coffee machine comprising a pressurized-hot-water sprinkler, and a dispenser cup facing the sprinkler and movable with respect to the sprinkler to and from an infusion position in which the dispenser cup is connected to the sprinkler; the dispenser cup housing a rigid sealed capsule for a measure of ground coffee; and the sealed capsule being closed at one end by a foil seal facing the sprinkler in use.
On known coffee machines employing sealed capsules, inflow of the pressurized hot water from the sprinkler is normally made possible by piercing the foil seal by means of a number of needles, which are moved through the foil seal when the dispenser cup is moved into the infusion position.
The normally conical or pointed cylindrical needles normally used to pierce the foil seal have created serious problems, owing to the fact that each needle, as it penetrates the foil seal, tends, on the one hand, to form the hole by forcing its way gradually through, and so permanently deforming, the foil seal, and, on the other, to adhere hermetically to the surface of the hole.
In actual use, finding the holes in the foil seal plugged hermetically by the respective needles, the pressurized hot water from the sprinkler tends, firstly, to implode the foil seal and compress the ground coffee inside the sealed capsule, and then to flow between the needles and holes or tear the foil seal. Whichever the case, the overpressure to which the ground coffee is subjected by the foil seal deforming inwards slows down the infusion process, thus resulting in poor-tasting coffee, and, in the event the foil seal is torn, the water tends to form preferential passages through, and only comes into contact with part of, the ground coffee in the sealed capsule. Once the coffee is made, the needles are withdrawn, and the overpressure inside the capsule is released violently through the holes unplugged by the needles, so that part of the ground coffee is normally also released, thus fouling the sprinkler.
It is an object of the present invention to provide a method of piercing a sealed capsule, designed to eliminate the aforementioned drawbacks.
According to the present invention, there is provided a method of piercing a sealed capsule on a coffee machine, the machine comprising a pressurized-hot-water sprinkler, and a dispenser cup facing said sprinkler and movable with respect to the sprinkler to and from an infusion position in which the dispenser cup is connected to said sprinkler; the dispenser cup housing a rigid sealed capsule for a measure of ground coffee; the sealed capsule being closed at one end by a foil seal facing the sprinkler in use; and the method comprising the step of forming a number of holes through said foil seal, and being characterized in that each said hole is formed by forming through the foil seal a number of cuts extending outwards from a common origin and each defining, together with each adjacent cut, a petal of a non-return blade valve.
The present invention also relates to a piercing device for piercing sealed capsules on a coffee machine.
According to the present invention, there is provided, on a coffee machine, a piercing device for piercing a sealed capsule, the machine comprising a pressurized-hot-water sprinkler, and a dispenser cup facing said sprinkler and movable with respect to the sprinkler to and from an infusion position in which the dispenser cup is connected to said sprinkler; the dispenser cup housing a rigid sealed capsule for a measure of ground coffee; the sealed capsule being closed at one end by a foil seal facing the sprinkler in use; and the piercing device being carried by said sprinkler in a position facing said dispenser cup, comprising a number of needles facing said dispenser cup, and being characterized in that each said needle comprises an active portion for penetrating said foil seal, and which, along the whole of its length, is in the form of a pyramid with concave faces.